Cancers are the most frequent type of human malignancies, and the fatality of cancer predominantly results from the dissemination of primary tumor cells to distant sites and the subsequent formation of metastases.
The causal implication of metastasis-inducing S100A4 protein, a member of the S100 family of calcium-binding proteins, in tumor progression, angiogenesis, and metastatic dissemination has been demonstrated by several approaches.
S100A4 plays a pivotal role in the tumor-stroma cross-talk that occurs between tumor cells and their stroma (including fibroblasts, endothelial, smooth muscle, inflammatory, and neural cells) mainly mediated by direct cell-cell contact or autocrine/paracrine cytokine and growth factor signalling. For example, epithelial growth factor, tumor growth factor-β1, and fibroblast growth factor-2 are able to stimulate the expression of S100A4 (Strutz et al. Kidney Int. 2002; 61(5):1714-1728); S100A4 released either by tumor or stroma cells into the tumor environment triggers pro-metastatic cascades in tumor cells (Grum-Schwensen et al. Cancer Res. 2005; 65(9):3772-3780); tumor cells or tumor-associated fibroblasts, in contrast to the normal fibroblasts, express high levels of S100A4 (Ambartsumian et al. Oncogene. 1996; 13(8):1621-1630); other host-derived tumor stroma cells, such as lymphocytes and macrophages, increase expression of S100A4 upon activation (Grigorian et al. Electrophoresis. 1994; 15(3-4):463-468).
S100A4 also influences tumor angiogenesis via the stimulation and remodelling of the extracellular matrix (production of degrading enzymes) and the motility of endothelial cells acting as a proangiogenic factor (Schmidt-Hansen et al. J. Biol. Chem. 2004; 279(23):24498-24504).
The S100A4 gene itself was originally isolated as a gene differentially expressed in highly metastatic mouse mammary adenocarcinoma (Ebralidze et al. Genes Dev. 1989; 3(7):1086-1093). It has also been demonstrated that the introduction of the S100A4 gene into non-metastatic tumor cell lines as well as its gene suppression in metastatic ones modified the tumorigenic and metastatic fate of such cells, therefore proving its involvement in tumor progression and metastasis formation (Lloyd et al. Oncogene. 1998; 17(4):465-473).
In the clinic, positive correlation between high levels of expression of S100A4 and poor prognosis in cancer patients has been demonstrated for breast carcinoma (Rudland P S et al. Cancer Res 2000. 60(6): 1595-1603), prostate carcinoma (Saleem M et al. PNAS 2006. 103(40): 14825-30), lung carcinoma (Tsuna M et al. Anticancer Res 2009. 29(7): 2547-54), colorectal carcinoma (Cho Y et al. World J Gastroent 2005. 11(31): 4852-6), pancreatic carcinoma (Rosty C et al. Am J Pathol 2002. 160(1): 45-50), renal carcinoma (Bandiera A et al. World J Surg 2009. 33(7): 1414-20), gastric carcinoma (Yonemura Y et al. Clin Cancer Res 2000. 6(11): 4234-42), ovarian carcinoma (Maelandsmo G M et al. Tumor Biol 2009. 30(1):15-25), papillary thyroid carcinoma (Min H S et al. Mod Pathol 2008. 21(6): 748-55), melanoma (Andersen K et al. Mod Pathol 2004. 17(8): 990-997), hepatocellular carcinoma (Cui J et al. J Can Res Clin Oncol 2004. 130(10): 615-22), bladder carcinoma (Agerbaek M et al. Eur Urol 2006. 50(4): 777-785), liposarcoma invasive carcinoma (Pazzaglia L et al. Anticancer Res 2004. 24(2B): 967-972), neuroblastoma (Bjornland K et al. J Pediatr Surg 2001. 36(7): 1040-44), esophageal squamous carcinoma (Ninomiya I et al. Int J Oncol 2001. 18(4): 715-20), osteosarcoma (Mathisen B et al. Clin Exp Metastasis 2003. 20(8): 701-11), gallbladder carcinoma (Nakamura T et al. Int J Oncol 2002. 20(5): 937-41), oral squamous carcinoma (Moriyama-Kita M et al. Oral Oncol 2004. 40(5): 496-500), endometrial carcinoma (Xie R et al. Lab Invest 2009. 89(8): 937-947), and medulloblastoma (Hernan R et al. Cancer Res 2003. 63(1): 140-148), amongst others.
Implications of S100A4 in various non-malignant pathological conditions have also been demonstrated by a number of research groups, in particular, in pathologies such as autoimmune inflammation and disorders in cardio-vascular, nervous, and pulmonary systems (Grigorian M et al. Current Molecular Medicine 2008. 8(6):492-6). S100A4 is therefore a candidate target for clinical applications. However, due to the complexity of the biological function of S100A4 and its unknown entire mechanism of action, no inhibitors yet exist that block either the intracellular or extracellular functions of this protein.
Antibody-based therapy has emerged as an integral part of effective treatments for a number of diseases. In the last decade, monoclonal antibodies have become major therapeutic agents in the treatment of malignant and nonmalignant diseases.
To date, monoclonal and polyclonal antibodies raised against S100A4 have been provided by different companies and research groups (Zhang et al, Calcium Binding Proteins 2006. 1:4, 219-223; ABIN167355 and ABIN171123 from antibodies-online GmbH, Germany; A5114 from DakoCytomation, Denmark; among others). Although scientific and patent teachings speculate on the therapeutic applications of these antibodies, to the best knowledge of the inventors, there is yet no evidence on file that the antibodies of the state of the art have actually solved the problem of treating cancer and non-malignant diseases.
WO2000064475 (Research Corporation Technologies, Inc.) discloses a method for the diagnosis of malignant cancer (i) by inhibiting the mts-1 protein with antibodies directed against the mts-1 protein (antibodies can be conjugated to a toxin) or (ii) by providing a nucleic acid encoding an antisense mts-1 nucleotide sequence.
Therefore, there is a need in the state of the art to provide new therapeutic approaches for the treatment of cancer, particularly for the treatment of angiogenesis and metastasis, targeting the S100A4 protein.
In addition, at a diagnostic level, S100A4 can be considered a good marker in the differentiation process of a normal cell towards a tumor cell, and therefore it is a good biomarker in the cytological examination of tumors. However, the detection of the expression of S100A4 in cancerous tissue presents the drawback of requiring a patient biopsy. Therefore, there is a need in the state of the art to provide a simpler and less invasive method for the clinical diagnosis of cancer by means of detecting the levels of S100A4 in a subject.